What progressive has a reading area that goes all the way across the lens

[optical24/7]

Tell him to purchase the lens from that other place if they will offer a money back guarantee if he’s not happy. And then tell him to return to you after he finds out that there is no PAL with near and intermediate all the way across the lens.

It’s impossible to make a progressive power ( or progressive prism for that matter) without having an umbilic corridor.

[KrystleClear]

Tell him to purchase the lens from that other place if they will offer a money back guarantee if he’s not happy. And then tell him to return to you after he finds out that there is no PAL with near and intermediate all the way across the lens.

It’s impossible to make a progressive power ( or progressive prism for that matter) without having an umbilic corridor.

I politely directed him elsewhere, because I just know that's a refund waiting to happen.

[waynegilpin]

If he is going to be able to read clearly out of the edge of the lens, can we assume that God has also redesigned his eyes?

[Uncle Fester]

Averted this potential disaster a few years ago when a patient came in with Foster grant multifocal readers.

Available in sphere powers only and the near was virtually edge to edge as a magnification,

Post #5:

https://www.optiboard.com/forums/showthread.php/65067-Multifocal-reading-glasses?highlight=Foster+grant+readers

[Lelarep]

Averted this potential disaster a few years ago when a patient came in with Foster grant multifocal readers.

Available in sphere powers only and the near was virtually edge to edge as a magnification,

Post #5:

https://www.optiboard.com/forums/sho...+grant+readers

So, it's essentially an executive style lineless trifocal? I don't think I've seen anything like that before.

[Uncle Fester]

So, it's essentially an executive style lineless trifocal? I don't think I've seen anything like that before.

https://www.fostergrant.com/reading-glasses/multi-focus

[uncut]

Ahhh...........2014.........what a wonderful year!

Good thread topic!

I wonder if Nikon's Online Wide NEO, Home and Office NEO, or Relaxsee NEO would qualify for inclusion in the "all across the bottom" category?

[AngeHamm]

Ahhh...........2014.........what a wonderful year!

Good thread topic!

I wonder if Nikon's Online Wide NEO, Home and Office NEO, or Relaxsee NEO would qualify for inclusion in the "all across the bottom" category?

Or even a Shamir Duo?

[Lelarep]

https://www.fostergrant.com/reading-glasses/multi-focus

How can they make the useful area across the entire width of the lens without a line?

What I don't understand is why they bother to put any +SPH at the top in the "interactive" zone. Why not make it plano?

[Uncle Fester]

How can they make the useful area across the entire width of the lens without a line? Is it because it is strictly a gradation of +SPH, since a typical progressive usually involves a -SPH transitioning towards positive?

What I don't understand is why they bother to put any +SPH at the top in the "interactive" zone. Why not make it plano?

I do not know either but I do know if someone with these comes in to be very wary what you promise your lenses can do.

I think they are really magnifiers and not refracting light.

[Robert Martellaro]

How can they make the useful area across the entire width of the lens without a line?

They can't. But then these are not general purpose PALs- the distance has about +0.75 D of the add power, reducing by the same amount the degree of progressivity, reducing the unwanted astigmatism proportionately, reducing the blur boundaries, especially for the lower value adds, to the point where the perceived blur is better tolerated.

Best regards,

Robert Martellaro

[Lelarep]

They can't. But then these are not general purpose PALs- the distance has about +0.75 D of the add power, reducing by the same amount the degree of progressivity, reducing the unwanted astigmatism proportionately, reducing the blur boundaries, especially for the lower value adds, to the point where the perceived blur is better tolerated.

Best regards,

Robert Martellaro

Ah, that would explain everything. They don't make the top portion plano to reduce the chance people will notice the oblique astigmatism, and the gradual nature of the + transition generally prevents people from noticing the oblique astigmatism during the transition as the lens adds more plus. That makes sense. I didn't think the lens had some kind of ultra secret sauce, because no matter how I tortured the associated equations, I couldn't make a progressive lens not produce oblique astigmatism.

[Robert Martellaro]

oblique astigmatism

Although OA is an aberration that causes blur towards the periphery of the lens, in this instance we are talking about 'unwanted surface astigmatism' that without exception, can be found around the umbilical line of all PALs, where the value is directly proportional to the add power.

For example, a two diopter add will generate about two diopters of cylinder/astigmatism.

Robert